Some members of a class of compounds containing the 1-(2-pyrimidinyl)-4-alkylenepiperazine moiety as represented by the formula: ##STR1## where n is 2 to 6 and R is ##STR2## and R.sup.1, R.sup.2 and R.sup.3 are independently hydrogen or loweralkyl, and exemplified by the compounds known as gepirone and ipsapirone, have been disclosed in U.S. Pat. No. 4,895,848 as being useful in the treatment of alcoholism. The related compound buspirone has been shown to lower the preference for alcohol in monkeys with a preference for alcohol. The three compounds buspirone, gepirone and ipsapirone are known serotonin receptor modulators, especially at the serotonin 5HT.sub.1A receptor subtype.
The European patent application EP 0356997A2 discloses the use of azapirone compounds in the treatment of substance addiction comprising over-eating, habitual use of tobacco, marijuana, cocaine, opiates, amphetamines, methylphenidate and related designer drugs and other recreational drugs. These compounds have been previously disclosed as psychotropic agents with useful anxiolytic properties and are encompassed by the formula: ##STR3## wherein: Z is selected from the group consisting of ##STR4## with R.sup.3 and R.sup.4 being independently selected from C.sub.1 -C.sub.4 alkyl and hydrogen or R.sup.3 and R.sup.4 can be taken together as a butanediyl or pentanediyl chain thereby forming a spiro ring system. The --NR.sup.1 R.sup.2 group can be taken as the 1-(2-pyrimidinyl)piperazinyl moiety or R.sup.1 is H and R.sup.2 is the group ##STR5## and A is selected from --CH.sub.2 --, --O--, --CH.sub.2 CH.sub.2 -- and --CH.dbd.CH--.
The patent disclosing the compounds useful in treating substance addiction includes the compounds buspirone, gepirone, ipsapirone, and zalospirone (3a,4,4a,6a,7a-hexahydro-2-[4-[4-(2-pyrimidinyl)-1-piperazinyl]butyl]-4,7- ethano-1H-cyclobut[f]isoindole-1,3(2H)-dione). The latter compound is disclosed in our U.S. Pat. No. 4,892,943 and in J. Med. Chem. 31(7), 1382-92 (1988) as having antipsychotic/anxiolytic properties with a low liability for extrapyramidal side effects and is classified as a 5HT.sub.1A modulator. Other N-[(4-arylpiperazin-1-yl)alkyl]bicyclicimides are disclosed in our U.S. Pat. No. 4,797,488 as antipsychotic/anxiolytic agents with low liability for extrapyramidal side effects.